1. Field of the Invention
The present invention relates to a switch device in which two switches are manipulated by two push-buttons, and the push surface of one of the push-buttons extends through an opening in the push-surface of the other button.
2. Description of the Prior Art
A conventional switch device of the type described above was disclosed in Japanese Utility Model Application (OPI) No. 153040/81. In this type of switch device, a first push-button is urged in a direction opposite to the pushing force by a helical spring. A push locking mechanism acts to hold the button in a pushed-down position after a first push and to release the button in response to a second push. A second push-button projects through an opening in the first push-button and is urged in a direction opposite to the pushing force by a second helical spring. A switch corresponding to each of the push-buttons is disposed within the switch device, each of which is operated by pushing the respective button.
An inherent problem with prior art devices is that when the second button is pushed after the first button is already in the pushed-in position, the first button is likely to be pushed by mistake, releasing the first button.